/*
 * This file is part of the TuxNES project codebase.
 *
 * Please see the README and COPYING files for more information regarding
 * this project.
 *
 * $Id: dynrec.c,v 1.9 2001/04/11 21:45:47 tmmm Exp $
 *
 * Description: This is the dynamic recompiler.  This takes 6502 code as
 * input, looks up the opcodes in the translation dictionary, evaluates
 * any expressions found therein, and writes the translated code to
 * *(next_code_alloc++). Pretty simple, huh?
 */

#include <stdio.h>
#include "mapper.h"
#include "globals.h"

u_char *next_code_alloc = CODE_BASE;

/* Some declarataions for the asm code */
unsigned int VFLAG;             /* Store overflow flag */
unsigned int FLAGS;             /* Store 6502 process status reg */
unsigned int STACKPTR;          /* Store 6502 stack pointer */
unsigned int PCR;               /* Store 6502 program counter */
void *XPC;                      /* Translated program counter */
signed int INRET;               /* Input data return value */
signed int CTNI;                /* Cycles to next interrupt */
unsigned int VRAMPTR;           /* address to read/write video memory */
unsigned int DMOD;              /* Dest addr to modify */
unsigned int LASTBANK;          /* Last memory page code executed in */

/* x86-specific definitions */
#define NOP 0x90
#define BRK 0xCC

/* forward and external declarations */
void disas(int);
void translate(int);

void
translate(int addr)
{
  int saddr;
  u_char src;
/*  unsigned int *ptr,*nptr; */
  unsigned int *ptr;
  unsigned char *sptr;
  unsigned char *cptr, *bptr;
  int slen, dlen;
  int x;
  u_char m, l, o;
  u_char stop = 0;

  XPC = cptr = next_code_alloc;
  if (disassemble)
    {
      printf ("\n[%4x] (%8x) -> %8x\n", addr, (int) (MAPTABLE[addr >> 12] +
                                                     addr), (int)cptr);
      disas (addr);             /* This will output a disassembly of the 6502 code */
    }
  while (!stop)
    {
      saddr = addr;
      INT_MAP[(MAPTABLE[addr >> 12] + addr) - RAM] = (unsigned int) cptr;
      ptr = (int *) TRANS_TBL;
      while (1)
        {
          src = *(MAPTABLE[addr >> 12] + addr);
          addr++;
          /*printf("%x%x",src>>4,src&0xF);fflush(stdout); */
          if (ptr[src] == 0)
            break;
          if (ptr[src] & 1)
            break;
          ptr = (int *) (ptr[src] + (int) TRANS_TBL);
        }
      if (ptr[src] == 0)
        {
          addr = saddr + 1;
	  /*printf("!%2x-NULL!",src); */
	  if (!ignorebadinstr)
	    *(cptr++) = BRK;
        }
      else
        {
          sptr = (u_char *) TRANS_TBL + ptr[src];
          slen = sptr[-1];
          dlen = x = *(sptr++);
          bptr = cptr;
          while (x--)
            *(cptr++) = *(sptr++);
          while (*sptr != 0)
            {
              m = *(sptr++);
              l = *(sptr++);
              o = *(sptr++);
              /*printf("[%c%d %d]",m,o,l);fflush(stdout); */
              if (m == '!')
                stop = 1;
              if (m == 'B')
                bptr[l] = *(MAPTABLE[(saddr + o) >> 12] + (saddr + o));
              if (m == 'C')
                bptr[l] = ~*(MAPTABLE[(saddr + o) >> 12] + (saddr + o));
              if (m == 'D')
                *((unsigned int *) (bptr + l)) = (unsigned int) bptr + l + o;
              if (m == 'E')
                *((int *) (bptr + l)) = *((signed char *) (MAPTABLE[(saddr +
                                                                     o) >>
                                                        12] + (saddr + o)));
              if (m == 'Z')
                *((unsigned int *) (bptr + l)) = (unsigned int) ZPMEM +
                  *(MAPTABLE[(saddr
                              +
                              o)
                             >>
                             12]
                    +
                    saddr
                    + o);
              if (m == 'A')
                *((unsigned int *) (bptr + l)) = (unsigned int) RAM +
                  *(MAPTABLE[(saddr
                              +
                              o)
                             >>
                             12]
                    +
                    saddr
                    + o)
                  + ((*(MAPTABLE[(saddr + o + 1) >> 12] + saddr + o + 1)) << 8);
              if (m == 'L')
                *((unsigned int *) (bptr + l)) = (unsigned int) RAM;
              if (m == 'W')
                *((unsigned short *) (bptr + l)) = *(MAPTABLE[(saddr + o) >>
                                                          12] + saddr + o) +
                  ((*(MAPTABLE[(saddr
                                +
                                o
                                +
                                1)
                               >>
                               12]
                      +
                      saddr
                      +
                      o
                      +
                      1))
                   << 8);
              if (m == 'X')
                *((unsigned int *) (bptr + l)) = (unsigned int) (MAPTABLE +
                                                         ((*(MAPTABLE[(saddr
                                                                       +
                                                                       o
                                                                       +
                                                                       1)
                                                                      >>
                                                                      12]
                                                             +
                                                             saddr
                                                             +
                                                             o
                                                             +
                                                             1))
                                                          >> 4));
              if (m == 'M')
                *((unsigned int *) (bptr + l)) = (unsigned int) (MAPTABLE);
              if (m == 'T')
                *((unsigned int *) (bptr + l)) = (unsigned int) STACK;
              if (m == 'P')
                *((unsigned short *) (bptr + l)) = saddr + o;
              if (m == 'R')
                *((int *) (bptr + l)) = *((signed char *) (MAPTABLE[(saddr +
                                                                     o) >>
                                                           12] + saddr + o))
                  + saddr + o + 1;
              if (m == 'J')
                *((unsigned int *) (bptr + l)) = *(MAPTABLE[(saddr + o) >>
                                                          12] + saddr + o) +
                  ((*(MAPTABLE[(saddr
                                +
                                o
                                +
                                1)
                               >>
                               12]
                      +
                      saddr
                      + o
                      +
                      1))
                   << 8);
              if (m == 'S')
                *((void **) (bptr + l)) = &STACKPTR;
              if (m == 'V')
                *((void **) (bptr + l)) = &VFLAG;
              if (m == 'F')
                *((void **) (bptr + l)) = &FLAGS;
              if (m == 'I')
                *((int *) (bptr + l)) = (int) (&INPUT) - (int) (bptr + l) - 4;
              if (m == 'O')
                *((int *) (bptr + l)) = (int) (&OUTPUT) - (int) (bptr + l) - 4;
              if (m == 'U')
                *((int *) (bptr + l)) = (int) (&U) - (int) (bptr + l) - 4;
              if (m == 'N')
                *((int *) (bptr + l)) = (int) (&NMI) - (int) (bptr + l) - 4;
              if (m == 'Y')
                *((int *) (bptr + l)) = (int) (Mapper[MAPPERNUMBER]) - (int)
                  (bptr
                   +
                   l) - 4;
              if (m == '>')
                bptr[l] += (((*((signed char *) (MAPTABLE[(saddr + o) >> 12]
                                                 + saddr + o)) + saddr + o +
                              1) & 0xFF00) != ((saddr + o + 1) & 0xFF00));
	      if (m == '^')
		bptr[l] = ignorebadinstr ? NOP : BRK;
            }
          addr = saddr + slen;
        }
    }
  while (((int) cptr & 15) != 0)
    *(cptr++) = NOP;
  next_code_alloc = cptr;
}